Fermentation and leaching of the organic fraction of municipal solid waste to improve methane production

Background

The anaerobic digestion of soluble substances extracted from the organic fraction of municipal solid waste (OFMSW) results in an enhanced rate and production of methane. However, the influence of substrate fermentation and subsequent leaching on methane output has yet to be investigated. This research aimed to examine the impact of combined fermentation and leaching processes over time on the degree of solubilization, fermentation by-products and, subsequently, the production of methane from fermented leachates and bagasses.

Results

The degree of solubilization observed in the non-leaching experiment was recorded at 12.7%, while the experiment utilizing daily leaching resulted in a solubilization of 22%. The fermented leachate collected at 24 h yielded 457 ± 75 NL CH₄ kg⁻¹ VS, which was 1.6 times greater than the methane production from the raw leachate of the OFMSW. In contrast, the fermented bagasse produced after 96 h demonstrated enhanced digestibility, resulting in 264 ± 26 NL CH₄ kg⁻¹ VS, or 1.5 times the methane production of the raw fermented bagasse of the OFMSW. The overall energy recoverable from the raw leachate and bagasse of the OFMSW amounts to 1103.6 kJ kg⁻¹ OFMSW. In contrast, the implementation of the fermentation-leaching method yields a total of 2482.6 kJ kg⁻¹ OFMSW.

Conclusions

By employing fermentation and subsequently leaching the OFMSW, a greater quantity of particulate substrate was solubilized, leading to an improved recovery of fermentation by-products. Moreover, both methane production and energy recovery experienced an increase, which can be attributed to the soluble substances extracted from the fermented leachate and the enhanced digestibility of the fermented bagasse. © 2025 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).